The present disclosure relates generally to uninterruptible power supply (UPS) systems, and more particularly, to UPS systems with battery back-ups.
UPS systems are often used to provide continuous power to a load in applications that require continuity of power, such as in hospitals and critical processes in both industrial and commercial settings, protecting equipment from power failure and interference from blackouts, brownouts, surges, and noise. FIG. 1 illustrates portions of a typical UPS system 10. A power supply line 12 is connected to a rectifier 14, which is connected to an inverter 16. A bypass power supply line 18 is connected in parallel with the main supply line 12. A static switch 20 is controlled to switch to the bypass line 18, bypassing the rectifier 14 and inverter 16 if any of those components fail. If the input power fails, a battery module 22 provides DC power to the inverter 16.
Three level battery boost converter topologies are sometimes used in UPS rectifiers. They provide several benefits, including lower component stress—resulting in increased reliability, less switches losses—resulting in greater efficiency and less heat rejected into the environs, and the ability to provide utility power-factor correction. However, battery boost converters add expense and complexity to UPS systems.
The present application addresses shortcomings associated with the prior art.